Elucidation of the mechanism of formation of thermally generated volatile and non-volatile Maillard reaction products using isotope labeling technique combined with ESI-TOF MS/MS and GC/MS analysis.

使用同位素标记技术结合 ESI-TOF MS/MS 和 GC/MS 分析，阐明热产生的挥发性和非挥发性美拉德反应产物的形成机制。

• 批准号: RGPIN-2014-03834
• 负责人: Yaylayan, Varoujan
• 金额: $ 2.19万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=669272
• 关键词: Elucidation; mechanism; formation; thermally; generated

Sugars and amino acids are the key components responsible for the generation of distinctive aroma and color of food products subjected to thermal processing. Many unpleasant-tasting raw foods can be transformed by the interaction of sugars and amino acids (known as Maillard reaction) into desirable products via processes such as bread baking, coffee roasting and chocolate manufacture. Under physiological conditions, many body proteins also can be modified through similar interaction with sugars, specially, in diabetic patients that may result in the impairment of physiological and immunological functions. Unfortunately, this same chemical interaction is also responsible for the thermal generation of food toxicants during cooking such as heterocyclic amines, acrylamide, furan and glycotoxins. Understanding the mechanism by which many of the above mentioned critical food components are formed can contribute to our ability to control their generation. Finding optimal conditions to lower the levels of different toxicants and at the same time retain the Maillard-derived aroma compounds and hence improve the quality and safety of foods, is one of the main challenges of the food industry today. **The long term objective of the applicant is to study the origin and the mechanism of formation of volatile and non-volatile compounds formed through the use of model systems. The applicant has developed a convenient method of introducing 13C- and 15N-labeled atoms into the reaction products, through carrying out the reactions with specifically labeled sugars (13C-1, 13C-2, .13C-6) and amino acids (15N, 13C-1, 13C-2 etc) using Pyrolysis-GC/MS as an integrated reaction, separation and identification system. The pyrolysis is conducted between 100-250oC for 20 seconds and requires only sub-milligram quantities of the expensive labeled precursors, thus reducing drastically the cost and time needed to carry out such experiments. Pyrolysis at 250°C for 20 seconds has been shown to mimic heating at 110oC for 1h. One of the advantages of using labeled reactants is that all the C- and N-atoms of a reaction product can be traced back to their origin in the starting material. This can permit elucidation of the mechanism of their formation and structural assignment of their mass spectral fragments. Using the above approach the applicant was able to elucidate the mechanism of formation of various thermally generated volatile and semi-volatile compounds relevant to food such as acrylamide, furan, pyrazines, etc. However, the polar residue remaining after the pyrolysis also contains considerable amount of chemical information in the form of labeled polar products. The short term objectives of the applicant is (1) to analyze these residues in selected model systems for their non-volatile components in addition to the volatiles. The strategy of analyzing the same sample for the volatiles and its residue for non-volatiles allows identification of label incorporation patterns of compounds in both fractions without having to perform additional experiments with costly labeled precursors and to mechanistically link the two pathways. The non-volatile residue can be a rich source of information regarding the origin of color, taste and toxicity due to recently identified link between the levels of consumption of heated foods (fried, grilled, etc.) and chronic diseases associated with aging. (2) To study the influence of selected food matrix components such as phenolics, salts etc on the direction of the Maillard reaction. These parameters have not been studied systematically.

糖和氨基酸是负责产生进行热加工的食品的独特香气和颜色的关键组成部分。许多令人不愉快的生食可以通过糖和氨基酸（称为Maillard反应）的相互作用（称为Maillard反应）通过面包烘烤，咖啡烘焙和巧克力制造等工艺来转化。在物理条件下，可以通过与糖的相似相互作用（特别是在糖尿病患者中，可能导致物理和免疫功能损害的糖尿病患者中的类似相互作用）来修饰许多人体蛋白质。不幸的是，这种相同的化学相互作用也负责烹饪过程中的热产生粮食有毒剂，例如杂环胺，阿什米德，呋喃和糖毒素。了解上述许多关键食品成分的机制可以有助于我们控制其一代的能力。找到最佳条件以降低不同毒物的水平，同时保留了Maillard衍生的香气化合物，因此可以提高食品的质量和安全性，这是当今食品行业的主要挑战之一。 **该应用的长期目标是研究通过使用模型系统形成的挥发性和非挥发性化合物的形成的起源和机理。该应用程序开发了一种方便的方法，该方法通过使用Pyrolesy-GC/MS作为集成反应和鉴定系统进行分离和识别系统，将13C和15N标记的原子引入反应产物中，并通过特定标记的糖（13C-1、13C-2，.13C-6）和氨基酸（13C-1、13C-2，.13C-6）和氨基酸（15N，13C-1、13C-2）进行反应。热解进行在100-250oC之间进行20秒，仅需要昂贵的标记前体的亚毫克量，从而大大降低了进行此类实验所需的成本和时间。在250°C下进行20秒的热解已显示在110oC时模仿1H。使用标记的反应物的优点之一是，可以将反应产物的所有C和N原子追溯到起始材料中的起源。这可以允许阐明其形成的机理和质谱片段的结构分配。使用上述方法，适用的能力能够阐明与食物相关的各种热产生的挥发性和半挥发性化合物的形成机制，例如丙烯酰胺，呋喃，吡啶，吡啶等。但是，在泛滥后，剩余的极性保留量还包含标有北极产物形式的化学信息的考虑。适用的短期目标是（1）除了挥发物外，还可以分析其非挥发性组件的选定模型系统中的这些残差。分析挥发物的相同样品的策略及其对非挥发性的残基允许鉴定这两种分数中化合物的标签掺入模式，而无需进行额外的实验，并具有成本昂贵的前体标记的前体并将两种途径连接起来。由于最近确定的加热食物消费水平（油炸，烤等）与与衰老相关的慢性疾病之间的联系，非易失性保留可以是有关颜色，味道和毒性起源的丰富信息来源。 （2）研究选定的食物基质成分（例如酚类，盐等）对Maillard反应方向的影响。这些参数尚未系统地研究。